Epidemiological and clinical studies indicate that genital infection with gonorrhea (GC) and chlamydia (CT) enhances HIV transmission and acquisition. A mainstay of gonorrhea and chlamydia prevention is identifying those individuals who are likely to transmit infection to the largest number of people, known as core transmitters. Currently, sexually transmitted infection (STI) prevention programs focus on identifying core transmitters among individuals who repeatedly self-refer to public STI clinics and fall within behaviorally- defined risk groups (i.e. commercial sex workers or drug users). However, this focus has not succeeded in controlling GC and CT in endemic communities, such as urban heterosexual minority populations. Clinics may miss core transmitters because many infected individuals do not seek out treatment. We envision this grant as the first step towards developing a place-based approach to STI control and prevention that will complement current clinic-based approaches and help realize the potential of the core group theory to eradicate GC and CT from local, endemic areas. However, prior to carrying out a full scale trial of venue- based screening, we must answer several preliminary questions which serve as the specific aims of this developmental study proposal. The specific aims are: 1) to determine whether there is a benefit of venue- based screening and treatment as a supplement to STI Clinic screening and treatment by comparing the yield of core transmitters, measured as the proportion of individuals screened who are GC and/or CT infected and who have concurrent sex partners, at venues and at an STI Clinic; 2) to determine what venue characteristics are associated with higher core transmitter yield; 3) to compare and contrast three methods for identifying venues; and 4) to estimate the catchment areas for high yield venues in order to determine the scale at which incidence of infection should be monitored to detect changes that might result from venue- based screening. We will adapt the PLACE method to identify and characterize partner meeting venues throughout the city of Baltimore. We will enroll 1000 18-35 years olds socializing at a sample of venues to estimate risk behaviors and disease prevalence among patrons of these venues. We will also examine the electronic patient records of 1000 individuals, 18-35 years old, seeking GC/CT testing at the Baltimore City Health Department STI Clinic. [unreadable] [unreadable] [unreadable]